參數(shù)資料
型號: LTC1955EUH
廠商: LINEAR TECHNOLOGY CORP
元件分類: 電源管理
英文描述: Dual Smart Card Interface with Serial Control
中文描述: 2-CHANNEL POWER SUPPLY SUPPORT CKT, PQCC32
封裝: 5 X 5 MM, 0.75 MM HEIGHT, MO-220WHHD, QFN-32
文件頁數(shù): 15/20頁
文件大?。?/td> 259K
代理商: LTC1955EUH
LTC1955
15
sn1955 1955fs
Interfacing to a Microcontroller
The serial port of the LTC1955 can be connected directly
to a 68HC11 style microcontroller’s serial port. The
microcontroller should be configured as the master device
and its clock’s idle state should be set to high (MSTR = 1,
CPOL= 1 and CPHA = 0 for the MC68HC11 family).
Figure4 shows the recommended configuration and di-
rection of data flow. Note that an additional I/O line is
necessary for LD to load the data once it has shifted around
the loop. Command data is latched into the command
register on the falling edge of the LD signal. The LTC1955
will begin to act on new command data as soon as LD goes
low. Any general purpose microcontroller I/O line can be
configured to control the LD pin.
The status of the LTC1955 is returned over the serial port.
Status data is latched into the shift register on the rising
edge of the LD pin. Whenever the system is waiting for
status data from the LTC1955, its LD pin should be held
low.
Figure 5. Microcontroller Interface
CARD A
CARD B
1955 F05
D
IN
D
OUT
SCLK
LD
LTC1955
MOSI
MISO
SCK
I/O
μ
CONTROLLER
Daisy-Chained Operation
For applications requiring more than two card sockets, the
serial port of the LTC1955 is designed to be easily daisy-
chained. The D
OUT
pin of one LTC1955 can be connected
directly to the D
IN
pin of another LTC1955. Rather than
sending two 8-bit bytes before asserting LD, the
microcontroller should send two 8-bit bytes per device.
LD should only be asserted after all devices have been
updated. Figure 7 shows three LTC1955s cascaded in
daisy chain fashion. In this case the microcontroller would
write six 8-bit bytes before asserting the LD pin. Alterna-
tively, if two serial ports are available on the microcontroller,
then two LTC1955s can be controlled independently.
If the DATA lines of two or more LTC1955s are connected
together, the static pull-up current will be the sum of the
devices. The static current can be brought back to the level
of a single LTC1955 by setting bit D3 on all but one of the
LTC1955s to 1 (see Table 1). Bit D3 disables the pull-up
current source on the DATA pin. This will help prevent V
OL
problems in multiple LTC1955 applications when driving
the DATA or I/O pins low.
APPLICATIU
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相關代理商/技術參數(shù)
參數(shù)描述
LTC1955EUH#PBF 功能描述:IC INTERFACE DL SMART CARD 32QFN RoHS:是 類別:集成電路 (IC) >> 接口 - 控制器 系列:- 標準包裝:2,450 系列:- 控制器類型:SPI 總線至 I²C 總線橋接 接口:I²C,串行,SPI 電源電壓:2.4 V ~ 3.6 V 電流 - 電源:11mA 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:24-VFQFN 裸露焊盤 供應商設備封裝:24-HVQFN(4x4) 包裝:托盤 配用:568-3511-ND - DEMO BOARD SPI TO I2C 其它名稱:935286452157SC18IS600IBSSC18IS600IBS-ND
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LTC1955IUH#PBF 功能描述:IC SMART CARD INTERFACE DL 32QFN RoHS:是 類別:集成電路 (IC) >> 接口 - 控制器 系列:- 標準包裝:2,450 系列:- 控制器類型:SPI 總線至 I²C 總線橋接 接口:I²C,串行,SPI 電源電壓:2.4 V ~ 3.6 V 電流 - 電源:11mA 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:24-VFQFN 裸露焊盤 供應商設備封裝:24-HVQFN(4x4) 包裝:托盤 配用:568-3511-ND - DEMO BOARD SPI TO I2C 其它名稱:935286452157SC18IS600IBSSC18IS600IBS-ND
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